When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Ok, so I'm planning on getting the 6637 air filter, but had a couple questions first. I tried doing a search on 6637, but I'm not real good with technology. So here goes.
1. A friend has a similar air filter system, but his has a divider to keep the cold air on that side of the engine. I don't see that in any of the pics for the 6637. Is this something that is important?
2. I really like my turbo whistle. I read the 6637 will accent my turbo whistle more than the stock air box. I have already defoiled the turbo pipe on one truck and liked the results. Will this bring it out even more?
3. The last thing that concerns me is the price. 6637 is only about $90 from Riff Raff, which I really like. However, I know the old adage of 'you get what you pay for.' If it was that price anywhere else, I probably would go more expensive, but Riff Raff has a great reputation, so I'm torn. I need to do something soon because the lid to my stock air box in the flatbed is warped. I just want to do it right, once. Thanks guys!
I ran a 6637 and was happy with it, except for the noise. Turbo sounds are nice but the sucking drone can get to ya. AIS fixes that, now it's as quiet as a library with a roaring 7.3 in the middle of it.
The divider is intended to ensure cold air goes into the engine. CAI would be the acronym, lots of makers. In theory it makes great sense, but on a boosted and intercooled engine the results don't seem to be spectacular. I recall an anecdote from Joe (CSIPSD), where a guy had his truck on the dyno and in back to back pulls ran a CAI, a 6637, and no intake at all. All 3 setups made about the same power. But I think if you like it, buy it. It's not going to hurt and they look cool.
The price on the 6637 is exactly why it is so popular. The big flow and good filtration without the big $$. Put a pre-filter on it to extend the life.
I have always been a firm believer that a CAI doesn't really matter when you are heating up your intake air 200+ degrees and then cooling it down a bunch again. That 20 degree difference will never get noticed.
The major flaw in the dyno test is that the CAI would need to be moving to make a difference.
Considering the 6637 kit is essentially a 4" diameter pipe, a clamp, a filter and a filter cover, the $90 is a relative bargain. Though I shop at Clay's as much as I can, you can rest good knowing you can pick up a replacement filter at any NAPA store (though they might have to ship it in from a regional, like ours has to do). Filter element through NAPA is close to $70 to give you an idea.
You can trust Clay at Riffraff. I've spent thousands with him over the past 4 months on my 7.3 rebuild. I shopped all the parts and always came back to order from Clay. That and although he's really a busy person, he'll help coach you or help you get the answers you need. Two Thumbs up for Riffraff.
For the money it is hard to beat the 6637, very good filtration, long service life, readily available replacements if something came up and if you search online you can find replacements around 30-35 bucks.
Clay's kit is great, I was thinking of piecing a kit together myself but the components he used like the T-bolt clamps where much nicer than anything I would have pieced together at home depot.
From what I've read about a basically stock to lightly modified truck. You have no reason to worry about fancy or expensive CAI kits. Or the air divider for that matter. The kit from Clay is great and is supposed to be a bit louder then the AIS kit that you will hear a lot about too.
Personally, I don't notice my 6637 being much louder then stock. Maybe my engine needs quieting down some?
The AIS kit is the next step up in filtration and only costs about twice as much. You don't need it for your truck though, the 6637 will be plenty sufficient. To top it off the AIS is known for and often bought because it is more quite.
I realize that the difference may be in the box but on the filters alone I was rather surprised to see thy wix rates the 6637 at flowing appx HALF of what the stock filter is rated for.
Does anyone know of a dyno test showing a 6637 vs stock.
Clay has them for $29 Riffraff Diesel: 6637 Replacement Filter , also if you watch him regularly, he does sales on them often, that's when you buy a few and always have them on hand!
I realize that the difference may be in the box but on the filters alone I was rather surprised to see thy wix rates the 6637 at flowing appx HALF of what the stock filter is rated for.
Does anyone know of a dyno test showing a 6637 vs stock.
Do a search on air filter flow rates. Theres been lots of tests and numbers put out there. I think Ernesteugene did some testing back in 08.
I realize that the difference may be in the box but on the filters alone I was rather surprised to see thy wix rates the 6637 at flowing appx HALF of what the stock filter is rated for.
Does anyone know of a dyno test showing a 6637 vs stock.
Wix doesn't specific at what restriction level that flow rate is. The filter was factory spec on larger and more powerful engines and people have run the 6637 up into the 400rwhp so I am not worried about flow.
I went with the 6637 because the previous owner of my truck had an AFE II on the truck. Replacement filters for them cost $$ and when I put the 6637 on, there was really no noticiable difference between the two.
Like stated already, you can't beat Clay's price for the kit. Very easy to install and looks great. Plus, I like representing Clay (Riffraff) and there awesome quality products.